For most people Britain"s bouncing economy, now growing at its fastest for three years, is cause for cheer. Not,【C1】______for those who manage the country"s electricity power system. For them【C2】______growth means faster progress towards a critical situation. Ofgem, the energy regulator, has long【C3】______that the margin between peak electricity demand and【C4】______supply is falling. In June it said the margin would【C5】______from 14% in 2014 to just 4% in the winter of 2018, increasing the risk of blackouts【C6】______the weather turn cold or a power station or two【C7】______ . Since that report Britain"s economy has grown fast. Ofgem"s assessment【C8】______that Britain would grow by about 1.6% in 2017. The Bank of England now【C9】______2.8% growth. This will【C10】______consumption. Over the past decade an increase in peak electricity demand of 0.5% 【C11】______each additional percentage point of economic growth. John Feddersen of Aurora Energy Research thinks the capacity margin will therefore【C12】______to 2.6% by 2018 unless action is taken. That【C13】______into a one-in-seven chance of shortages, up from the one-in-twelve chance【C14】______was thought most likely last summer. Falling coal prices have kept Britain"s coal-fired power stations running at full【C15】______. That means many will have to close sooner than was【C16】______because European environmental laws【C17】______the total number of operating hours left to them. At the same time cheap coal has made electricity from gas uncompetitive, 【C18】______operators to put some gas-fired plants into long-term【C19】______. Renewable capacity cannot yet make up the【C20】______.